1. Field of the Invention
The present invention relates to the liquid-gas separation system now variously, and collectively, called the in-line centrifugal, vortical, and gas recycling system. More specifically, the invention relates to generating the centrifugal force of separation and the pressure pattern for gas recycling.
2. Description of the Prior Art
Porta-Test Manufacturing Ltd., Edmonton, Alberta, Canada, a company of Alberta is the face-owner of U.S. Pat. No. 3,481,118, dated Dec. 2, 1969. The system of this patent discloses the generation of centrifugal force on liquid-entraining gas to wet the walls of a tube from which the liquid is skimmed through a gap in the wall. The gas, which also flows through the gap, is recycled and discharged as liquid-stripped gas.
The corporate history of Porta-Test is uncertain, but U.S. Pat. No. 3,793,812, dated Feb. 26, 1974 is apparently owned by Porta-Test also. The '812 patent aligns with commercial literature enough to affirm Porta-Test is embodying the principle of centrifugal force generation in a pipe unit which can be duplicated in the multiples to meet the quantity demand of separation problems. It is the arrangement for generating the centrifugal force and the recycle pressure system that needs improvement.
The field conditions to be met are generally well known in the art. The '812 patent addresses the conditions somewhat narrowly. Natural gas transmission lines are described as entraining liquid quantities in the order of 1 to 10 gal./MMscf. The specifications, generally, are to remove 99%, or over, of 5 micron, and larger, liquid drops of this entrained liquid. Of course it is expected to carry out this removal with as little pressure drop as possible through any separating structure.
The applications for this separating structure are not limited to transmission lines. There are separating demands close to the well-head, in the production flow stream. Here the oil and water that is not bound up in an emulsion may be roughly separated by baffled vessels into separate compartments. However, the gas may entrain liquids of 5 microns and greater. It is this separation problem which is addressed.
Porta-Test is only one manufacturer who applies gas recycling vortical tube to the problem. The Perry Equipment Corporation has developed a so-called "Cyclotube" separation system which falls in this category. Perry uses a structure to spin the mixture processed which is technically different from the "Whirly Jig" of the Porta-Test system. However, both systems skim the centrifuged liquids from their tube wall and recycle the gas portion applied in expelling the liquids through an opening in the tube wall.
There remains in the art a problem in increasing the centrifuging force on the liquids and simplifying the structure required to generate the differential pressure to recycle the carrier gas.